const sum = (num1, num2) => num1 + num2;

const sub = (num1, num2) => num1 - num2;

const PI = 3.14;

let name = "tom";

let person = {
  name: "jack",
  age: 18
};

// 前面是导出名, 后面是导出的变量
module.exports = {
  summary: sum,
  sub: sub,
};
// 导出名与变量名相同时,可以简写
module.exports = {
  PI,
  person
};
